Marathon Training Plan — 16 Weeks Preparation
16 weeks is the sweet spot for marathon training: long enough to build fitness from a reasonable base, short enough to stay focused. This plan walks through the four phases, the three key sessions per week, and the 3-week taper that gets you to the start line strong.
The structure: Base (4 weeks) → Build (5 weeks) → Specific (5 weeks) → Taper (2–3 weeks). Three quality sessions per week — long run, midweek workout, weekend tempo or marathon-pace run — with easy runs filling the rest.
Prerequisites
- Currently running 4+ days per week, comfortable with a 14–16 km long run
- No injuries — marathon training amplifies any existing weakness
- Realistic goal time based on a recent half marathon or 10K (use VDOT to predict)
- Schedule willing to absorb 6–10 hours per week at peak
The four phases
Phase 1 — Base (Weeks 1–4)
Goal: build aerobic volume. Mostly Zone 2 running with strides and occasional hills.
| Week | Long run | Mid-week quality | Total km/week | Peak Training Load |
|---|---|---|---|---|
| 1 | 16 km easy | Strides 6×100 m | 40–50 | 250–300 |
| 2 | 18 km easy | Hills 6×30 sec | 45–55 | 280–340 |
| 3 | 20 km easy | Strides 8×100 m | 50–60 | 320–380 |
| 4 (recovery) | 14 km easy | Easy | 30–40 | 180–230 |
Phase 2 — Build (Weeks 5–9)
Goal: introduce threshold work and longer long runs. Quality sessions become the centerpiece.
| Week | Long run | Mid-week workout | Total km/week | Peak Training Load |
|---|---|---|---|---|
| 5 | 22 km easy | 3×8 min @ T pace | 55–65 | 380–450 |
| 6 | 24 km easy | 4×8 min @ T pace | 60–70 | 420–490 |
| 7 | 26 km easy | 5×1 km @ T pace | 65–75 | 460–530 |
| 8 (recovery) | 18 km easy | 20 min @ T pace | 40–50 | 240–290 |
| 9 | 28 km with last 5 km @ M pace | 6×1 km @ T pace | 65–75 | 490–560 |
Phase 3 — Marathon-Specific (Weeks 10–14)
Goal: simulate race-day demands. Long runs include marathon-pace blocks; midweek workouts shift toward race-specific intervals.
| Week | Long run | Mid-week workout | Total km/week | Peak Training Load |
|---|---|---|---|---|
| 10 | 30 km, 8 km @ M pace at end | 2×3 km @ T pace | 70–80 | 540–620 |
| 11 | 32 km, 10 km @ M pace at end | 3×3 km @ T pace | 75–85 | 580–680 |
| 12 (recovery) | 22 km easy | 20 min @ T pace | 50–60 | 290–350 |
| 13 | 34 km, 12 km @ M pace at end | 2×5 km @ HM pace | 75–90 | 600–700 |
| 14 (peak) | 32 km with 16 km @ M pace | 3×4 km @ T pace | 80–95 | 640–740 |
Phase 4 — Taper (Weeks 15–16)
Goal: reduce fatigue while preserving fitness. Volume drops; intensity stays.
| Week | Long run | Mid-week workout | Total km/week | Peak Training Load |
|---|---|---|---|---|
| 15 | 22 km, last 8 km @ M pace | 3×1 km @ T pace | 55–65 | 340–410 |
| 16 (race week) | 12 km easy on Tuesday | 2×1 km @ M pace Wed | 30–40 + race | 180 + 280 |
Pace targets per goal time
| Goal | Marathon (M) | Threshold (T) | Easy (Z2) | Long run (Z2) |
|---|---|---|---|---|
| 5:00 marathon | 7:06/km | 6:30/km | 7:30–8:15/km | 7:45–8:30/km |
| 4:30 marathon | 6:23/km | 5:50/km | 6:50–7:30/km | 7:00–7:45/km |
| 4:00 marathon | 5:41/km | 5:15/km | 6:15–6:50/km | 6:25–7:00/km |
| 3:30 marathon | 4:58/km | 4:35/km | 5:30–6:00/km | 5:40–6:10/km |
| 3:00 marathon | 4:16/km | 3:55/km | 4:45–5:10/km | 4:55–5:25/km |
| 2:45 marathon | 3:54/km | 3:35/km | 4:25–4:50/km | 4:30–4:55/km |
The three variants
First marathon (just finish)
- Cap long runs at 30 km — beyond that, recovery cost outweighs the benefit for first-time finishers
- Skip M-pace blocks until the last 4 weeks — focus on time on feet
- Target peak weekly: 60–70 km
Sub-4 marathon
- Two M-pace long runs per cycle, 14–18 km at M pace
- Threshold sessions weekly during build phase
- Peak weekly: 70–85 km
Sub-3 marathon
- Three M-pace long runs per cycle, including a 30 km with 20 km at M pace
- Threshold + VO₂max blocks; peak week with 5×1 mile at threshold
- Peak weekly: 90–110 km
The three non-negotiables
- Recovery weeks every 4 weeks. Drop volume by 40%. Skip these and you'll arrive at the start line stale or injured.
- One marathon-pace long run every 2–3 weeks in Phase 3. Race-day specificity matters — your legs need to know what 30+ km at M pace feels like.
- Honest tapering. Reduce volume 40% in week 15, another 30% in week 16. Resist the temptation to do "one more" hard session — fitness is already banked.
Race-day Form target
Aim for Form +15 to +25 on race morning. Fitness should still be 75–95 (depending on your peak). Lower Form means you're under-tapered; much higher means Fitness has dropped too far.
Common mistakes
- Skipping the long M-pace runs. They're the highest-return single session in the plan.
- Racing the threshold sessions. T pace is by feel "comfortably hard" — not 5K pace. Stay in zone.
- Big mileage jumps. No more than 10% volume increase per week in build phases. Fitness ramp > 5/week is risky.
- New shoes on race day. Break in race shoes for 100+ km in long runs first.
- Ignoring sleep. Fitness of 80 with 6 hours of sleep is worse than Fitness of 65 with 8 hours.
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Frequently asked questions about marathon training
Is 16 weeks enough for a first marathon?
If you're already running 4+ days/week with a 14 km long run, yes. If you're starting from less, plan a 4-week base block before week 1 — that's a 20-week build in total.
How long should the longest long run be?
For most runners, 32–35 km. Going longer than 35 km adds little fitness and a lot of recovery debt. The exception: sub-3 runners doing M-pace simulations may run 32 km with 20+ km at M pace.
Can I race a half marathon during the plan?
Yes — week 11 or 13 is a great spot. Treat it as a tune-up, not a goal race; recover for 5–7 days afterward.
What if I miss a week from illness?
Drop the missed week from the plan; don't try to make it up. Resume at the volume you were at before, or 80% of it if illness was severe. Adaptive AI plans (like WattRun's) auto-recompute around missed weeks.
Do I need to do a 32 km long run?
Not necessarily. Many sub-3:30 runners cap their long run at 28–30 km but with significant M-pace blocks (12–16 km at marathon pace). Time on feet matters; absolute distance is secondary.